Vascular device for emboli, thrombus and foreign body removal and methods of use

ABSTRACT

Apparatus and methods are provided for use in filtering emboli from a vessel and/or performing thrombectomy and embolectomy, wherein a vascular device comprises one or more support hoops connected near a distal end of a guide wire, each support hoop having an articulation region, and a blood permeable sac affixed to the support hoop or hoops to form a mouth of the blood permeable sac. The mouth of the sac closes when the apparatus is collapsed for removal to prevent material from escaping from the sac.

REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.12/190,319, filed Aug. 12, 2008, which is a continuation of U.S.application Ser. No. 10/302,433 filed Nov. 22, 2002, now U.S. Pat. No.7,410,491, which is a continuation of U.S. patent application Ser. No.09/636,040, filed on Aug. 9, 2000, now U.S. Pat. No. 6,544,279, which isa continuation-in-part of U.S. patent application Ser. No. 09/470,682filed Dec. 23, 1999, now U.S. Pat. No. 6,214,026; U.S. Pat. No.6,544,279 is also a continuation-in-part of U.S. patent application Ser.No. 09/470,703 filed Dec. 23, 1999, now U.S. Pat. No. 6,179,861; U.S.Pat. No. 6,544,279 is also a continuation-in-part of U.S. patentapplication Ser. No. 09/470,857 filed Dec. 23, 1999, now U.S. Pat. No.6,129,739; U.S. Pat. No. 6,544,279 is also a continuation-in-part ofU.S. patent application Ser. No. 09/430,211 filed Oct. 29, 1999, nowU.S. Pat. No. 6,589,263; U.S. Pat. No. 6,544,279 is also acontinuation-in-part of U.S. patent application Ser. No. 09/364,064filed Jul. 30, 1999, now U.S. Pat. No. 6,530,939; U.S. Pat. No.6,544,279 is also a continuation-in-part of U.S. patent application Ser.No. 09/470,681 filed Dec. 23, 1999, now U.S. Pat. No. 6,203,561; andU.S. Pat. No. 6,544,279 is also a continuation-in-part of U.S. patentapplication Ser. No. 09/611,428 filed Jul. 7, 2000, now U.S. Pat. No.6,616,679.

FIELD OF THE INVENTION

The present invention relates to apparatus and methods for filtering orremoving matter from within a vascular system. More particularly, thepresent invention provides a low profile self-expanding vascular deviceuseful for capturing emboli or foreign bodies generated duringinterventional procedures, and for thrombectomy and embolectomy.

BACKGROUND OF THE INVENTION

Percutaneous interventional procedures to treat occlusive vasculardisease, such as angioplasty, atherectomy and stenting, often dislodgematerial from the vessel walls. This dislodged material, known asemboli, enters the bloodstream, and may be large enough to occludesmaller downstream vessels, potentially blocking blood flow to tissue.The resulting ischemia poses a serious threat to the health or life of apatient if the blockage occurs in critical tissue, such as the heart,lungs, or brain.

The deployment of stents and stent-grafts to treat vascular disease,such as aneurysms, also involves the introduction of foreign objectsinto the bloodstream, and also may result in the formation of clots orrelease of emboli. Such particulate matter, if released into thebloodstream, also may cause infarction or stroke.

Furthermore, interventional procedures may generate foreign bodies thatare left within a patient's bloodstream, thereby endangering the life ofthe patient. Foreign bodies may include, for example, a broken guidewire, pieces of a stent, or pieces of a catheter.

Numerous previously known methods and, apparatus have been proposed toreduce complications associated with embolism, release of thrombus, orforeign body material generation. U.S. Pat. No. 5,833,644 to Zadno-Aziziet al., for example, describes the use of a balloon-tipped catheter totemporarily occlude flow through a vessel from which a stenosis is to beremoved. Stenotic material removed during a treatment procedure isevacuated from the vessel before the flow of blood is restored. Adrawback of such previously known systems, however, is that occlusion ofantegrade flow through the vessel may result in damage to the tissuenormally fed by the blocked vessel.

U.S. Pat. No. 5,814,064 to Daniel et al. describes an emboli filtersystem having a radially expandable mesh filter disposed on the distalend of a guide wire. The filter is deployed distal to a region ofstenosis, and any interventional devices, such as angioplasty balloonsor stent delivery systems, are advanced along the guide wire. The filteris designed to capture emboli generated during treatment of the stenosiswhile permitting blood to flow through the filter. Similar filtersystems are described in U.S. Pat. No. 4,723,549 to Wholey et al. andU.S. Pat. No. 5,827,324 to Cassell et al.

One disadvantage of radially expandable filter systems such as describedin the foregoing patents is the relative complexity of the devices,which typically comprise numerous parts. Connecting more than a minimalnumber of such parts to a guide wire generally increases deliverycomplications. The ability of the guide wire to negotiate tortuousanatomy is reduced, and the profile of the device in its deliveryconfiguration increases. Consequently, it may be difficult or impossibleto use such devices in small diameter vessels, such as are commonlyfound in the carotid artery and cerebral vasculature. Moreover, suchfilter devices are generally incapable of preventing material fromescaping from the filter during the process of collapsing the filter forremoval.

International Publication No. WO 98/39053 describes a filter systemcomprising an elongated member, a radially expandable hoop and acone-shaped basket. The hoop is affixed to the elongated member, and thecone-shaped basket is attached to the hoop and the elongated member, sothat the hoop forms the mouth of the basket. The filter system includesa specially configured delivery catheter that retains the mouth of thebasket in a radially retracted position during delivery.

While the filter system described in the foregoing InternationalPublication reduces the number of components used to deploy thecone-shaped basket, as compared to the radial strut-type filter elementsdescribed hereinabove, it too has drawbacks. Chief among these, it isexpected that it will be difficult to reduce the diameter of theradially expandable hoop to its retracted position. In particular, asthe hoop is contracted through smaller radii of curvature, the stiffnessof the hoop is expected to increase dramatically. This increasedstiffness prevents the hoop from being contracted more tightly, and isexpected to result in a delivery profile too large to permit use of thedevice in critical regions of the body, such as the smaller coronaryarteries, carotid arteries, and cerebral vasculature.

In view of the foregoing disadvantages of previously known apparatus andmethods, it would be desirable to provide a vascular device, e.g., foruse as a vascular filter, that overcomes such disadvantages and employsfew components.

It would be desirable to provide a reliable and multi-functionaldelivery system for use with the vascular device.

It would be desirable to provide an integrated vascular device with athrombectomy element and a vascular filter.

It also would be desirable to provide a vascular device that is capableof being contracted to a small delivery profile, thus permitting use ofthe device in small vessels.

It further would be desirable to provide a vascular device that iscapable of being contracted to a sufficiently small profile that it maybe retrieved using the guide wire lumen of previously known treatmentdevices, and without the need for specialized delivery catheters.

It still further would be desirable to provide a vascular device thatreduces the risk of emboli or thrombus removed from the vessel wallescaping from the device when the device is collapsed and removed.

It also would be desirable to provide a vascular device that permits arapid exchange deployment modality.

SUMMARY OF THE INVENTION

In view of the foregoing, it is an object of the present invention toprovide a vascular device that overcomes disadvantages of previouslyknown vascular filters, thrombectomy/embolectomy and foreign bodyremoval devices, and employs few components.

It is an object of the present invention to provide a reliable andmulti-functional delivery system for use with the vascular device.

It is an object to provide an integrated vascular device with athrombectomy element and a vascular filter.

It also is an object of this invention to provide a vascular device thatis capable of being contracted to a small delivery profile, thuspermitting use of the device in small vessels.

It is a further object to provide a vascular device that is capable ofbeing contracted to a sufficiently small profile that it may beretrieved using the guide wire lumen of previously known treatmentdevices, and without the need for specialized delivery catheters.

It is another object to provide a vascular device that reduces the riskof emboli or thrombus removed from the vessel wall escaping from thedevice when the device is collapsed and removed.

It also is an object to provide a vascular device that permits a rapidexchange deployment modality.

These and other objects of the present invention are accomplished byproviding a vascular device, suitable for use as a vascular filter orthrombectomy/embolectomy device that comprises a blood permeable sacaffixed at its perimeter to a support hoop having an articulationregion. The support hoop is attached to a distal region of an elongatedmember, such as a guide wire, and supports a proximally-oriented mouthof the sac when the device is deployed in a vessel. The device may alsocomprise a nose cone to facilitate percutaneous introduction, and adelivery sheath having one or more lumens. The lumens may further beconfigured for a rapid exchange mode of introduction along the guidewire.

In a first embodiment, the support hoop includes one or morereduced-thickness articulation regions that enable the support hoop tobe contracted to very small radii of curvature without the problems ofincreased stiffness and kinking of previously known devices. In analternative embodiment, the articulation region may comprise a gap inthe support hoop bridged by the perimeter of the blood permeable sac.

The support hoop preferably also has a curved profile that prevents thearticulation region, when folded, from damaging the wall of the vessel.The curved profile permits the device to effectively contact the wallsof the vessel and reduce emboli or thrombus removed from the vessel wallfrom bypassing the sac. Moreover, the articulation region, when combinedwith a support hoop having a curved profile, causes the sides of thesupport hoop to fold inwards towards one-another when the vasculardevice is collapsed into a sheath for removal. This, in turn, closes themouth of the sac and reduces the potential for emboli or thrombus to bereleased from the vascular device during removal.

Advantageously, use of an articulation region permits vascular devicesof the present invention to be contracted to very small diameters,thereby enabling the use of delivery catheters having diameters as smallas 3 Fr. Moreover, the vascular devices may be retracted within theguide wire lumens of conventional treatment devices, such as angioplastycatheters and stent delivery systems, thereby obviating the need tore-insert a specialized delivery catheter to remove the vascular device.However, a retrieval sheath having a distal region that flares orexpands outwardly to receive the emboli-filled sac upon completion of aninterventional procedure, and which reduces risk of rupture to the sac,optionally may be provided in accordance with the present invention.

In embodiments suitable for use as embolic filters, the vascular devicemay include a separate guide wire for introducing treatment devicesproximal of the deployed vascular device. Additionally, the vasculardevice may have a second support hoop attached to the distal end of thesac. During retrieval, multiple hoops ensure that emboli are retainedwithin the sac and prevent the sac from bunching. Where multiple hoopsare rotated, they may be arranged such that they rotate independently ofthe guide wire, thereby reducing risk that the sac wall will becometwisted during advancement.

In alternative embodiments, sac bunching is mitigated by tapering thesac and attaching it to one or more support hoops, or to the guide wire.Sac porosity may also be specified to ensure passage of blood cells andcapture of emboli, as well as to control a pressure drop across thevascular device. In other embodiments, a delivery sheath is providedthat permits a lesion to first be crossed with an unencumbered guidewire prior to passing the vascular device across the lesion. In stillfurther embodiments, several support hoops may be provided at the mouthof a single sac to facilitate opening and closing of the sac.

In thrombectomy applications, a separate thrombectomy element may beprovided in addition to the vascular filter. The thrombectomy elementmay be attached to the elongated member proximal of the vascular filteror may comprise a separate catheter. In a preferred embodiment, thethrombectomy element is similar in construction to the vascular filterand may be refracted independently. Alternatively, the thrombectomyelement may be any conventional atherectomy device used in conjunctionwith the vascular filter and may be advanced and refracted either inconjunction or independently of the vascular filter.

A delivery system in accordance with the present invention, configuredfor use with the vascular devices described herein, is also provided.The delivery system integrates the functions of a Touhy Borst, atorquer, and a pusher into a single device, thereby facilitatingintroduction and retrieval of embodiments of the present invention. Thetorqueing function allows a vascular device to navigate tortuousanatomy. For example, the distal end of a guide wire may be rotated toselectively orient the vascular device in a selected branch of abifurcated vessel. The Touhy-Borst adapter permits liquid to beintroduced or withdrawn through the lumen of the vascular devicedelivery catheter. The pusher feature of the delivery system allowsdeployment and refraction of the vascular device from within thedelivery catheter.

Methods of using embodiments of the present invention are also provided,including use of novel radiopaque features, and use of a previouslyknown balloon catheter to arrest antegrade flow through a vessel untilthe vascular device of the present invention is deployed.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects and advantages of the present invention willbe apparent upon consideration of the following detailed description,taken in conjunction with the accompanying drawings, in which likereference characters refer to like parts throughout, and in which:

FIGS. 1A and 1B are, respectively, a side-sectional view of a previouslyknown vascular device contracted within a delivery sheath, and an endview of that vascular device deployed in a vessel;

FIGS. 2A and 2B are, respectively, a perspective view of a vasculardevice constructed in accordance with the principles of the presentinvention in a deployed state, and a detailed view of the articulationregion of the device of FIG. 2A;

FIG. 3 is a perspective view of the vascular device of FIG. 2 in afolded configuration, prior to removal;

FIG. 4 is a plan view of the vascular device of FIG. 2;

FIGS. 5A-5D are side sectional views depicting a method of deploying,using, and retrieving the vascular device of FIGS. 2-4;

FIG. 6 is a perspective view of an alternative embodiment of a vasculardevice of the present invention in a deployed state;

FIGS. 7A and 7B are, respectively, a perspective view and a plan view ofa further alternative embodiment of the present invention in a deployedstate;

FIGS. 8A-8E are sectional views of a vascular device disposed withinalternative embodiments of delivery sheaths of the present invention;

FIG. 9 is a side view of a previously known balloon catheter;

FIGS. 10A-10D are views illustrating the steps of using the ballooncatheter of FIG. 9 with the vascular device of FIG. 2;

FIGS. 11A-11C are perspective views of further alternative embodimentsof vascular devices constructed in accordance with the principles of thepresent invention;

FIG. 12 is a perspective view of an alternative embodiment of thevascular device of the present invention with two support hoops, shownin a deployed state;

FIG. 13 is a perspective view of an alternative embodiment of thevascular device of FIG. 12 with a smaller distal support hoop;

FIG. 14 is a perspective view of a still further alternative embodimentof the vascular device of FIG. 12 that allows the vascular device toindependently rotate with respect to the guide wire;

FIG. 15 is a perspective view of an alternative embodiment of thepresent invention with a tapered blood permeable sac, shown in adeployed state;

FIG. 16 is a perspective view of a radiopaque support hoop constructedin accordance with one aspect of the present invention;

FIGS. 17A-17C illustrate another alternative embodiment of the vasculardevice of the present invention in which the articulation regioncomprises a gap in the support hoop bridged by the perimeter of theblood permeable sac;

FIGS. 18A and 18B are side-sectional views depicting an integratedvascular device of the present invention suitable for thrombectomy,disposed, respectively, within a delivery sheath and in a deployedstate;

FIGS. 19A-19E are side-sectional views depicting a method of deploying,using, and retrieving the integrated vascular device of FIG. 18;

FIGS. 20A and 20B are side-sectional views depicting an alternativeembodiment of the integrated vascular device of FIG. 18, disposed,respectively, within a delivery sheath and in a deployed state;

FIGS. 21A and 21B are side sectional views of a delivery systemconstructed in accordance with the present invention coupled to thevascular device of FIG. 5A, shown, respectively, in a deliveryconfiguration and in a deployed configuration;

FIGS. 22A-22E are side sectional views depicting a method of deploying,using, and retrieving a vascular device of the present invention inconjunction with a specially configured retrieval sheath; and

FIGS. 23A and 23B are side sectional views depicting a method of usingand retrieving the vascular device in conjunction with an alternativeembodiment of the specially configured retrieval sheath.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIGS. 1A and 1B, some of the disadvantages associated withpreviously known vascular devices, such as the emboli filters describedin the above-mentioned International Publication WO 98/39053, aredescribed. In FIG. 1, the vascular filter comprises guide wire 10 havinghoop 12 coupled to its end. Filter sac 14 is affixed to hoop 12, so thatwhen delivery catheter 16 is retracted proximally and guide wire 10 isheld stationary, hoop 12 radially expands to contact the walls of vesselV.

As described hereinabove, one difficulty with such vascular filters isthat the hoop used to support the filter sac experiences increasedstiffness when contracted to small diameters, i.e., due to the sharpdirectional change at the tip of the hoop, thereby limiting the minimumdelivery profile achievable for such instruments. Although this effectmay be reduced by decreasing the thickness of the wire employed in hoop12, at the point at which the wire becomes sufficiently thin toaccommodate the bending stresses, the wire is too thin to effectivelyradially expand and urge the filter sac into engagement with the vesselwall.

On the other hand, as shown in FIGS. 1A and 1B, the bending stressesimposed upon the hoop of such previously known devices, if drawn withina delivery catheter, may be sufficiently high to result in the formationof kink 18 at the tip of the hoop. This “kinking” effect becomes moresevere in sheaths having a small inner diameter. Thus, for example,applicant has observed that when sheaths having inner diameters of0.035″ or smaller are used, a hoop of nitinol or multi-strand nitinolcable having a diameter of 0.0055″ will form kink 18 Kink 18 in turn mayapply relatively high localized pressure and friction against wall 17 ofsheath 16, thereby making the vascular filter difficult to deploy. Inparticular, the kink may impale wall 17 of delivery sheath 16 and maymake it difficult or impossible to deploy the vascular filter,especially in tortuous anatomy.

In addition, when the filter is subsequently deployed in vessel V, asshown in FIG. 1B, kink 18 may deform the pre-formed shape of hoop 12,impairing the ability of the filter to seal against the walls of vesselV. This may in turn lead to the presence of gaps G between the perimeterof the hoop and the vessel wall, depending upon the severity of thekink. Consequently, emboli may pass through the gaps with antegrade flowand significantly reduce the efficacy of the filter. Additionally, kink18 may be sufficiently sharp to damage or dissect the wall of vessel Vwhen the filter is deployed.

The vascular device of the present invention solves the above-describeddisadvantages, providing a vascular device, suitable for use as avascular filter or thrombectomy/embolectomy device, with aself-expanding support hoop that is sufficiently thick to radiallyexpand and urge a blood permeable sac into engagement with the vesselwall, but which includes an articulation region that overcomes theproblems associated with kinking. In particular, the vascular device ofthe present invention includes a reduced thickness articulation regionand a pre-formed curved profile that avoids the difficulties ofpreviously known systems while providing a high degree of efficacy incapturing emboli or thrombus, and ease of deployment and retrieval.

Referring now to FIGS. 2A and 2B, vascular device 20 constructed inaccordance with the principles of the present invention, illustrativelyan embolic filter, comprises guide wire 22, support hoop 24 havingarticulation region 26, and blood permeable sac 28 affixed to supporthoop 24. Sac 28 is coupled to support hoop 24 so that the support hoop24 forms an opening for the sac. Support hoop 24 preferably is connectedto guide wire 22 near distal end 23 of the guide wire.

Sac 28 preferably is constructed of a thin, flexible biocompatiblematerial, such as polyethylene, polypropylene, polyurethane, polyester,polyethylene tetraphlalate, nylon or polytetrafluoroethylene, orcombinations thereof. The material should be sufficiently thin, suchthat the sac is non-thrombogenic. Sac 28 includes openings or pores 30that permit blood cells to pass through the sac substantiallyunhindered, while capturing any larger emboli, thrombus, or foreignbodies that may be released during a procedure, such as angioplasty orstent placement. In a preferred embodiment, sac 28 has openings or pores30 in a range of about 20 to 400 microns in diameter, and morepreferably, about approximately 80 microns. These pore sizes permit redblood cells (which have a diameter of approximately 5 microns) to easilypass through the sac, while capturing thrombus or emboli.

Pores 30 are preferably formed by a laser drilling process. For example,a thin sheet of the flexible biocompatible material may be thermoformedto create sac 28, for example, by stretching the sheet over a mandrel,by dip forming, or by blow molding. Sac 28 may alternatively befabricated from an extruded tube of the biocompatible material. A flatmetal mask, with tiny holes approximately the size of pores 30, may thenbe placed in front of the sac. A laser having a beam diameter equal toor greater than the diameter of the material illuminates the mask. Thelaser beam passes through the holes in the mask and strikes thematerial, thereby forming pores 30 in sac 28.

Laser drilling may also be accomplished with a laser having a beamdiameter approximately the size of pores 30, in which case pores 30 maydrilled individually. Sac 28 may alternatively comprise a wovenmaterial, for example, formed from the above-mentioned polymers, havinga pore diameter determined as a function of the pattern and tightness ofthe weave.

Support hoop 24 comprises a hoop having a circular or rectangularcross-section that is formed of a super-elastic material, such as anickel-titanium alloy (“nitinol”). During deployment and retrieval ofvascular device 20, described hereinafter, support hoop 24 folds in halfand collapses to fit within a small diameter delivery sheath. Whenvascular device 20 is in a deployed state, as depicted in FIG. 2A,support hoop 24 resumes its pre-formed shape. Support hoop 24 preferablycomprises nitinol wire, although it may also be formed from amulti-strand nitinol cable, a spring tempered stainless steel, or othersuper-elastic material.

In accordance with the principles of the present invention, support hoop24 includes one or more reduced-thickness articulation regions 26, andpre-formed curved regions 34. As depicted in FIG. 2B, articulationregion 26 includes a region having reduced thickness t.sub.1 compared tothickness t of the remainder of support hoop 24. Articulation region 26and curved regions 34 enable support hoop 24 to fold with apre-determined shape when vascular device 20 is collapsed to acontracted state for delivery or retrieval.

In FIG. 2B, articulation region 26 is depicted as a localized reductionin the thickness of support hoop 24, as may be achieved, for example,using conventional grinding, chemical etching, or electroless polishingprocesses. Alternatively, support hoop 24 may be continuously taperedalong its circumference, so that articulation region 26 results from amore gradual reduction in the wall thickness of the support hoop.Tapering support hoop 24 may permit greater flexibility in the vicinityof articulation region 26, thus enabling support hoop 24 to fold moreeasily at the articulation region. Such tapering of the thickness of thesupport hoop along a portion of its circumference also may reduce thepotential for stress-induced fracture typically associated with abruptchanges in diameter.

In a preferred embodiment of vascular device 20 of the presentinvention, vascular device 20 easily fits within a delivery sheathhaving an inner diameter of 0.033″, and, more preferably, may be usedwith a delivery sheath having an inner diameter as small as 0.026″. Thedeployed diameter of support hoop 24 preferably is approximately 7 mm,while guide wire 22 preferably has a diameter of 0.014″. The distal endof guide wire 22 also may be tipped with a spring section or coil tip,as is per se known.

Support hoop 24 preferably is constructed of 0.00551″ nitinol wiretapered (by a grinding, chemical etching, or electroless polishingprocess) to 0.0025″ at articulation region 26. Specifically,articulation region 26 preferably consists of a length about 0.05″ longand having a diameter of 0.0025″, coupled on either side to curvedregions 34. Each of curved regions 34 includes a length of wire that istapered from a diameter of 0.055″ to a diameter of 0.0025″ over a lengthof about 0.025″. Support hoop 24 also may include radiopaque features,such as gold or platinum bands 33, spaced at intervals around thecircumference of support hoop 24, or a coil of radiopaque materialwrapped around the support hoop, as described hereinafter with respectto FIG. 16, or a gold plated coating.

Referring to FIGS. 3 and 4, additional features of vascular device 20are described. FIG. 3 depicts vascular device 20 of FIG. 2A in acontracted state, while FIG. 4 illustrates a directional change insupport hoop 24 preferably caused by the presence of curved regions 34.Advantageously, use of articulation region 26 and the curved profile ofsupport hoop 24 introduced by curved regions 34 also cause support hoop24 to fold in half during retrieval. As shown in FIG. 3, support hoop 24folds in half, effectively closing the mouth of blood permeable sac 28and preventing the escape of collected emboli or thrombus. This featurealso may permit the use of a smaller or shallower sac than wouldotherwise be possible, without increasing the risk of material escapingfrom the device when the sac is collapsed for retrieval. Use of asmaller or shallower sac also enables vascular device 20 to be deliveredin a smaller delivery sheath, having an inner diameter as small as0.026″ for the preferred embodiment.

Referring now to FIGS. 5A-5D, methods of using the vascular device ofthe present invention as a vascular filter are described. In FIG. 5A,guide wire 22 and delivery sheath 40 are manipulated into positionwithin vessel V using well-known percutaneous, techniques. Vasculardevice 20 of FIG. 2A is disposed in its contracted delivery state withindistal end 42 of delivery sheath 40, and delivery sheath 40 is advancedthrough the vessel using distal end 23 of guide wire 22. Articulationregion 26 and curved regions 34 of support hoop 24 enable the sides ofthe support hoop to fold together and become elongated when drawn withindelivery sheath 40. The size of delivery sheath 40 and guide wire 22have been exaggerated to illustrate structure. In reality, the diameterof delivery sheath 40 is approximately an order of magnitude smallerthan the internal diameter of vessel V.

With respect to FIG. 5B, once delivery sheath 40 is disposed at adesired location within a patient's vessel V, such as a coronary arteryor carotid artery, as determined, for example, by the position ofradiopaque band 43 under a fluoroscope, guide wire 22 is held stationarywhile delivery sheath 40 is refracted proximally. Alternatively,delivery sheath 40 may be held stationary while guide wire 22 isadvanced. In either case, when vascular device 20 is no longer confinedwithin delivery sheath 40, support hoop 24 expands to seal against thewalls of vessel V. When in its deployed state, curved regions 34 ofsupport hoop 24 orient articulation region 26 concentrically against theinside wall of the vessel, thus reducing the risk of impaling the vesselwall, as might be expected of the kinked support hoop of FIG. 1B. Bloodcontinues to flow unimpeded through vessel V in direction D.

In FIG. 5C, once vascular device 20 is deployed in vessel V, otherinterventional instruments, such as angioplasty catheters, atherectomydevices, or stent delivery systems may be advanced along guide wire 22to position such devices at treatment zones located proximally ofvascular device 20. For example, in FIG. 5C, angioplasty ballooncatheter 44 has been advanced along guide wire 22 to a position proximalof vascular device 20 to trap emboli E, i.e., pieces of plaque dislodgedfrom the walls of vessel V by balloon 46.

With respect to FIG. 5D, upon completion of the angioplasty procedureusing angioplasty balloon catheter 44, guide wire 22 is pulledproximally to cause the sides of support hoop 24 to collapse together toclose the mouth of sac 28 (see FIG. 3). Additional proximal retractionof guide wire 22 causes support hoop 24 and sac 28 to enter at leastpartially within the guide wire lumen of angioplasty catheter 44. Asdepicted in FIG. 5D, only a portion of support hoop 24, neararticulation region 26, and a distal portion of sac 28 extend out of theguide wire lumen of angioplasty catheter 44. Alternatively, vasculardevice 20 may be fully retracted within the guide wire lumen.Angioplasty catheter 44 then is withdrawn with vascular device 20 andany trapped emboli E.

Advantageously, the compliant design of vascular device 20 permits thedevice to be contracted to its delivery state within the guide wirelumen of conventional previously known interventional devices.Accordingly, unlike previously known vascular devices, which requireremoval of the interventional device followed by re-insertion of aspecially designed catheter to retrieve the vascular device, the systemof the present invention reduces the time, effort and trauma of thisadditional step. Instead, the vascular device may be readily closed andretrieved upon completion of the interventional procedure.

Vascular device 20 alternatively may be used in performingthrombectomy/embolectomy. In this case, the vascular device is deployedin a vessel at a location distal to a lesion, in the manner depicted inFIGS. 5A and 5B. Once support hoop 24 is deployed into contact with thevessel wall, vascular device 20 may be retracted proximally to scrapealong the wall of the vessel, and excise thrombus so that it is capturedin sac 28. Delivery sheath 44 may then be re-inserted into the vesselalong guide wire 22, and vascular device 20 is retracted and removedfrom the vessel. Additional thrombectomy embodiments are describedhereinbelow with respect to FIGS. 18-20.

As discussed hereinabove, sac 28 is porous so that blood cells may passthrough while emboli E are captured. As seen in FIG. 5B, if the sum ofthe area of all these pores A.sub.1 is less than the internalcross-sectional area A.sub.2 of vessel V, a pressure drop is expectedacross the vascular device. This may lead to hemolysis and insufficientdownstream flow. If A.sub.1 is greater than or equal to A.sub.2, thepressure drop is expected to decrease. Proper selection of pore diameter(in the range of 20-400 microns) and pore density ensures that A.sub.1is greater than or equal to A.sub.2.

Selection of a larger pore diameter within the provided range may alsoreduce the pressure drop by decreasing drag as blood passes through sac28. Drag may further be decreased by providing elliptical pores throughthe sac that project round relative to bloodflow when sac 28 isdeployed. Furthermore, the porosity of sac 28 may be specified suchthat, if distal pores become occluded with thrombus, emboli, etc.,proximal pores remain open to ensure continuous blood flow. It shouldalso be noted that flow through vessel V is substantially unaffected byplacement of sac 28 and hoop 24 in the flow path.

Referring now to FIG. 6, an alternative embodiment of the vasculardevice of the present invention, again illustratively a vascular filter,is described. Vascular device 50 comprises guide wire 51 and supporthoops 52 and 53 connected to blood permeable sac 54. As discussedhereinabove, vascular device 50 includes articulation regions 55 and 56formed at the intersection of opposing curved regions 57 and 58 ofsupport hoops 52 and 53. Sac 54 preferably also is connected to guidewire 51 along its entire length, thereby providing more controlleddeployment and removal of vascular device 50. Support hoop 53 serves tostabilize and deploy the distal portion of sac 54. In addition, affixingsac 54 to guide wire 51 may provide a more compact arrangement within adelivery sheath, and prevent bunching of the sac material.

In FIGS. 7A and 7B, a further alternative embodiment of the vasculardevice of the present invention is described. Vascular device 60, shownin the deployed state, comprises guide wire 61 having multi-turn helicalsupport hoop 63 connected at weld point 62. Blood permeable sac 64 isaffixed to the distal-most portion of support hoop 63. Support hoop 63includes one or more side turns 65 that terminate in curved regions 66,as described hereinabove. Curved regions 66 in turn are joined togetherby articulation region 67. Preferably, side turns 65 are coupled to oneanother and to the distal region of guide wire 61, e.g., by a weld bead,at point 68.

In accordance with this aspect of the present invention, vascular device60 may be contracted to small profile delivery state. When deployed froma delivery catheter, such as delivery sheath 40 of FIG. 5A, side turns65 expand into contact with the walls of the vessel proximal to thelocation at which curved regions 66 contact the vessel wall. Side turns65 serve to stabilize the support hoop 63 and sac 64 when vasculardevice 60 is deployed within a blood vessel. In addition, side turns 64are expected to assist in orienting the axis of support hoop 63 and sac64 in alignment with the longitudinal axis of vessel V. Accordingly,support hoop 63 is expected to reduce the risk of tilting of thevascular device within the vessel, and thus enhance the safety andreliability of the device.

Referring now to FIGS. 8A-8E, several embodiments of a delivery sheathsuitable for use with the vascular device of the present invention aredescribed. Each of these embodiments are designed to permit thephysician to first pass a guide wire across a lesion before passing thevascular device of the present invention across the lesion. Thus, therisk of generating emboli, during the step of positioning the vasculardevice of the present invention distal to a lesion, is expected to bereduced.

In particular, in FIG. 8A, vascular device 70 of the present inventioncomprises guide wire 71, support hoop 72 and blood permeable sac 73folded in a contracted delivery state within lumen 74 of delivery sheath75. Vascular device 70 is similar in design to vascular device 20 ofFIG. 2A, except that device 70 includes nose cone 76 affixed to distalregion 77 of guide wire 71. Delivery sheath 75 includes hemostaticfitting 78 at its proximal end and guide wire lumen 79.

In accordance with the methods of the present invention, vascular device70 and guide wire 80 are used as follows. First, unencumbered guide wire80 is advanced through a vessel until distal region 81 of the guide wirecrosses a lesion. The proximal end of guide wire 80 then is insertedinto the distal end of guide wire lumen 79 of delivery sheath 75 usingpreviously known “over the wire” techniques.

Delivery sheath 75 then is advanced over guide wire 80, which is heldstationary, until nose cone 76 and a distal portion of the deliverysheath cross the lesion. Once support hoop 72 and sac 73 of vasculardevice 70 are positioned distal to the lesion, guide wire 80 iswithdrawn from the vessel and delivery sheath 75 is refractedproximally, thereby deploying vascular device 70 to its deployed state.As will of course be understood, nose cone 76 remains in the vessel,distal to sac 73, during deployment of the vascular device. Uponcompletion of use of vascular device 70, delivery sheath 75 may onceagain be advanced along guide wire 71 and the support hoop and sacretracted within lumen 74 of delivery sheath 75. Alternatively, aninterventional device may be advanced over guide wire 71 to perform amedical procedure, and the vascular device may be retrieved within aguide wire lumen of the interventional device, as discussed hereinabovewith respect to FIG. 5.

Vascular device 90 of FIG. 8B is similar in construction to that of FIG.8A, and includes guide wire 91, support hoop 92, blood permeable sac 93and nose cone 94. Delivery sheath 95 includes lumen 96 housing device90, guide wire lumen 97, and hemostatic fitting 98. Guide wire lumen 97opens through skive 99 in lateral wall 100 of delivery sheath 95. Guidewire 101 therefore may be used in accordance with well-known “rapidexchange” techniques, wherein the length of unencumbered guide wire 101may be significantly shorter than in the case of the “over the wire”arrangement depicted in FIG. 8B. Operation of delivery sheath 95 andvascular device 90 is similar to that described hereinabove with respectto FIG. 8A, except that the proximal end of unencumbered guide wire 101is passed through the distal end of lumen 97 and passes out throughskive 99.

In FIG. 8C, delivery sheath 105 includes lumen 106 that opens throughthe lateral wall via skive 107, and guide wire lumen 108 that opensthrough the lateral wall via skive 109. Accordingly, as will be apparentto one of ordinary skill, both vascular device 110 and guide wire 112may be used as described hereinabove with respect to FIG. 8A and furtherin accordance with “rapid exchange” techniques.

Vascular device 113 of FIG. 8D is similar in construction to thosedescribed hereinabove. Delivery sheath 114 includes lumen 115, guidetube 116, and hemostatic fitting 117. Lumen 115 houses device 113 duringdelivery and retrieval. Guide tube 116 comprises guide wire lumen 118,which is configured to receive unencumbered guide wire 119. Inoperation, the proximal end of guide wire 119 is passed through guidewire lumen 118 of guide tube 116. Thus, guide wire 119 may be used inaccordance with “rapid exchange” techniques described with respect toFIG. 8B and with “over the wire” techniques described with respect toFIG. 8A.

Vascular device 120 of FIG. 8E is also similar to those describedhereinabove. Delivery sheath 121 includes lumen 122 and hemostaticfitting 123. Lumen 122 houses device 120. Guide wire 124 is coupled toand terminates at the proximal end of delivery sheath 121. Thus, distalend 126 of guide wire 125 of vascular device 120 is first to cross thelesion. Then, nose cone 127, attached to guide wire 125, and a distalportion of delivery sheath 121 cross the lesion. Guide wire 124 andattached delivery sheath 121 are retracted proximally, thereby deployingvascular device 120 to its deployed state. Device 120 may then beretrieved within sheath 121 or within an interventional device, asdiscussed hereinabove.

Referring now to FIG. 9, a previously known balloon catheter isdescribed. Catheter 130 is constructed of materials typically used incatheters, such as polyethylene or polyurethane, and includes compliantballoon 131 disposed in distal region 132. Compliant balloon, which maybe formed of nylon or latex, is inflated using inflation port 133 atproximal end 134 of the catheter. Catheter 135 also includes hemostaticport 136 and an interior lumen through which a delivery sheath may beadvanced to pass out of an opening in distal end 137.

With respect to FIGS. 10A-10C, a method of using catheter 130 of FIG. 9in conjunction with the vascular device of the present invention isdescribed. In accordance with this aspect of the present invention,antegrade blood flow through a vessel is occluded while a vasculardevice constructed in accordance with the present invention is advancedacross a lesion. Once the vascular device, illustratively a vascularfilter, is deployed, the balloon is deflated, thereby permittingantegrade flow to be established. Importantly, because flow through thevessel is stopped prior to deployment of the vascular device, few or noemboli are expected to bypass the filter.

More particularly, with respect to FIG. 10A, catheter 130 is disposed invessel V at a location proximal to lesion L, with the vascular device ofthe present invention disposed in its contracted delivery state indelivery sheath 138. In FIG. 10B, balloon 131 is inflated via inflationport 133 to engage the interior wall of vessel V, thereby arrestingantegrade flow in the vessel.

As shown in FIG. 10C, delivery sheath 130 then is advanced across lesionL so that the support hoop and sac of the vascular device will bedisposed distal to lesion L when deployed. During this step, deliverysheath 138 may generate emboli E as it passes across the lesion.However, because antegrade flow in the vessel is stopped, the emboliwill not travel distally in the vessel.

With respect to FIG. 10D, once vascular device 140 is deployed, so thatsupport hoop 141 and sac 142 span vessel V, balloon 131 is deflated.This, in turn, causes antegrade flow to become re-established in vesselV, urging emboli E into sac 142. Catheter 130 then may be withdrawn, andadditional treatment devices advanced along guide wire 143 of vasculardevice 140. Removal of vascular device 140 may be by any of the methodsdescribed hereinabove with respect to FIG. 5D.

Referring now to FIGS. 11A-11C, still further alternative embodiments ofvascular devices constructed in accordance with the present inventionare described. Each of the devices of FIGS. 11A-11C, which are shown inthe deployed state, includes two or more support hoops to support theblood permeable sac. Each of those support hoops in turn includes anarticulation region that permits the sides of the support hoops tocollapse inwards to each other as described hereinabove with respect toFIGS. 3 and 4.

Specifically, in FIG. 11A vascular device 150, illustratively an embolicfilter, comprises guide wire 151, support hoops 152 and 153 havingarticulation regions 154 and 155, respectively, and blood permeable sac156 affixed to support hoops 152 and 153. Sac 156 is coupled to supporthoops 152 and 153 so that the support hoops form an opening for the sac.Support hoops 152 and 153 preferably are connected to guide wire 151near its distal end.

Sac 156 is also attached to the distal end of guide wire 151 at point157. Sac 156 preferably is constructed of a thin, flexible biocompatiblematerial, as for the embodiments described hereinabove, and includesopenings or pores 158 that permit blood cells to pass through the sacsubstantially unhindered, while capturing any larger material that maybe released during a procedure such as angioplasty or stent placement.Pore sizes are selected as described hereinabove with respect to FIG.2A.

Support hoops 152 and 153 comprise hoops having circular or rectangularcross-sections that are formed of a super-elastic material, such as anickel-titanium alloy (“nitinol”). During deployment and retrieval ofvascular device 150, support hoops 152 and 153 fold in half and collapseto fit within a small diameter delivery sheath. When the delivery sheathis retracted, support hoops 152 and 153 resume their pre-formed shapeand deploy the perimeter of sac 156 into contact with the vessel walls.Support hoops 152 and 153 preferably comprise a nitinol wire, but alsomay be formed from a multistrand nitinol cable, or other super-elasticmaterial.

In accordance with the principles of the present invention, supporthoops 152 and 153 are affixed to guide wire 151 at ring 159 and includereduced-thickness articulation regions 154 and 155, constructed asdescribed hereinabove. More particularly, support hoops 152 and 153 arepre-formed to form structures having curved regions 160 and 161,respectively, so that articulation regions 154 and 155 are disposed in aportion of the support hoop that is approximately concentric with avessel wall when vascular device 150 is deployed. Articulation regions154 and 155 and curved regions 160 and 161 thus enable support hoops 152and 153 to fold with a pre-determined shape when vascular device 150 iscollapsed to a contracted state for delivery or retrieval.

In a preferred embodiment of vascular device 150 of the presentinvention, vascular device 150 easily fits within a delivery sheathhaving an inner diameter of 0.033″, and more preferably, may be usedwith a delivery sheath having an inner diameter as small as 0.026″. Thedeployed diameter of vascular device 150 preferably is approximately 7mm.

Compared to vascular device 20 of FIGS. 2-4, vascular device 150 of FIG.11A employs two support hoops instead of one and provides centrallocation of guide wire 151 and attachment of blood permeable sac 156 tothe distal end of the guide wire. These differences may provide morecontrolled deployment and removal of vascular device 150. In addition,affixing sac 156 to guide wire 151 may provide a more compactarrangement within a delivery sheath, and prevent bunching of the sacmaterial.

Referring now to FIG. 11B, another alternative embodiment of thevascular device of the present invention, again illustratively avascular filter, is described. Vascular device 170 is similar inconstruction to vascular device 150, except that vascular device 170employs three support hoops instead of two. Device 170 comprises guidewire 151 and support hoops 171, 172 and 173 connected to blood permeablesac 156.

As discussed hereinabove, vascular device 170 includes articulationregions 174, 175 and 176 formed at the intersection of opposing curvedregions 178, 179 and 180 of support hoops 171, 172 and 173. Supporthoops 171, 172 and 173 preferably are connected to the distal end ofguide wire 151 at ring 177. Sac 156 preferably also is connected toguide wire 151 at point 157. Vascular device 170 is expected to providesimilar advantages to those contemplated for vascular device 150.

With reference to FIG. 11C, yet another alternative embodiment of thevascular device of the present invention, again illustratively avascular filter, is described. Vascular device 190 is similar inconstruction to vascular devices 150 and 170, except that vasculardevice 190 employs four articulated support hoops. Device 190 comprisesguide wire 151 and support hoops 191, 192, 193 and 194 connected toblood permeable sac 156, with articulation regions 195, 196, 197 and 198formed at the intersection of opposing curved regions 200, 201, 202 and203 of the respective support hoops 191-194. Support hoops 191-194 arepreferably connected to the distal end of guide wire 151 at ring 199.

Alternative embodiments of vascular devices of the present inventionhave been described with one to four support hoops. As will be apparentto one of ordinary skill in the art of interventional device design, anynumber of support hoops may be used with minor modifications to thedesigns described hereinabove.

Referring now to FIGS. 12-15, further alternative embodiments of thevascular device of the present invention are described. In FIG. 12,vascular device 250, illustratively an embolic filter, comprises guidewire 252, support hoops 253 and 254 having articulation regions 255 and256, respectively, and blood permeable sac 258 affixed to support hoops253 and 254. Sac 258 is coupled to support hoop 253 at its proximal endso that the support hoop forms an opening for the sac. Sac 258 iscoupled to support hoop 254 at its distal end to prevent emboli fromspilling from sac 258 during retrieval. Support hoops 253 and 254preferably are connected to guide wire 252 near distal end 259 of theguide wire. Sac 258 has openings or pores 260 that permit red bloodcells to easily pass through the sac.

During deployment and retrieval of vascular device 250, support hoops253 and 254 expand and collapse as discussed hereinabove with respect tosupport hoop 24 of FIG. 2. Support hoops 253 and 254 are attached toguide wire 252 at attachment points 261 and 262, respectively, andfurther comprise curved regions 263 and 264, respectively. Support hoops253 and 254 may include radiopaque features, such as gold or platinumbands 265, spaced at intervals around the circumference of the hoops.

Applicant expects that vascular device 250 may further reduce the riskthat captured emboli could spill during retrieval, and also may providea better seal against the artery.

With reference to FIG. 13, an alternative embodiment of vascular device250 that prevents bunching is disclosed that may provide even furtherbenefits. Vascular device 270 comprises guide wire 272 on which proximalsupport hoop 273 and distal support hoop 274 are disposed. The proximaland distal portions of blood permeable sac 275 are affixed to supporthoops 273 and 274, respectively. Proximal support hoop 273 is attachedto distal end 271 of guide wire 272 at attachment point 276 and includesarticulation region 277 and curved regions 278. Likewise, distal supporthoop 274 is attached to guide wire 272 at attachment point 279 andincludes articulation region 280 and curved regions 281. Sac 275includes blood permeable pores 282. Hoops 273 and 274 may includeradiopaque features, such as gold or platinum bands 283, spaced atintervals around the circumference of the hoops.

Proximal support hoop 273 is significantly larger in circumference thandistal hoop 274. Proximal hoop 273 seals against the artery walls anddefines the diameter of the mouth of sac 275. Smaller distal hoop 274prevents emboli from spilling from sac 275 when retrieving device 270.It also allows the diameter of sac 275 to decrease along its length.This taper in sac 275 is expected to reduce the risk that sac 275 willbunch when the sac is retrieved. Sac 275 may further by attached toguide wire 272.

Applicant has determined that where multiple support hoops are employed,as in the embodiments of FIGS. 12 and 13, twisting of the guide wireduring deployment may prevent the sac of the vascular device fromproperly sealing against the vessel wall. For example, if guide wire 252in the embodiment of FIG. 12 is rotated after distal hoop 254 has beendeployed, but before proximal hoop 253 has been deployed, proximal hoop253 may deploy at an angle with respect to distal hoop 254. This, inturn, may constrict, or all together close, the opening of sac 258,thereby rendering the vascular device ineffective.

FIG. 14 discloses a vascular device in accordance with the presentinvention that overcomes problems associated with twisting of the guidewire during deployment. Vascular device 290 comprises guide wire 292with distal end 293, and support hoops 294 and 295. Support hoops 294and 295 further comprise articulation regions 296 and 297, respectively,and curved regions 298 and 299, respectively. The proximal and distalportions of blood permeable sac 300 are attached to support hoops 294and 295, respectively. Sac 300 includes pores 301. Support hoops 294 and295 are attached to sheath 302 at attachment points 303 and 304,respectively. Sheath 302 preferably comprises a flexible, 0.001″ thicktube made of a biocompatible material, such as polyamide orpolytetraethylene. Guide wire 292 passes through the lumen of sheath302. Sheath 302 is able to rotate with respect to guide wire 292 but istranslationally restrained by stops 305 and 306, for example, solderbeads.

By attaching support hoops 294 and 295 to sheath 302, rotationalproblems are mitigated. Sheath 302 only transmits translational motionof guide wire 292 to support hoops 294 and 295. Thus, twisting momentsapplied to wire 292 will not affect the performance of vascular device290. Sac 300 may also be attached to sheath 302.

With reference to FIG. 15, a further alternative embodiment of thevascular device of the present invention is disclosed that also preventsbunching. Vascular device 310 comprises guide wire 312 on which supporthoop 313 is disposed. Tapered blood permeable sac 314 is affixed tosupport hoop 313. Hoop 313 is attached to distal end 311 of guide wire312 at attachment point 315 and includes articulation region 316 andcurved regions 317. Tapered sac 314 includes blood permeable pores 318.Hoop 313 may include radiopaque features, such as gold or platinum bands319, spaced at intervals around the circumference of the hoop.

As with vascular device 270 of FIG. 13, the diameter of tapered sac 314decreases along its length to reduce the risk of bunching when the sacis retrieved. Tapering also reduces the amount of material that must fitwithin the lumen of a delivery sheath, and thereby allows a deliverysheath of smaller profile to be used. Furthermore, tapering the bloodpermeable sac reduces the risk that the sac will snag on a stent duringretrieval.

Because vascular device 310 lacks the distal support hoop of theembodiments of FIGS. 12 and 13, there is a reduced risk of problemsassociated with twisting. In a preferred embodiment, the diameter at thedistal end of tapered sac 314 is less than the internal diameter of theretrieval sheath with which the apparatus is used. Tapered sac 314 mayoptionally be attached to guide wire 312, for example, to furthermitigate bunching.

Referring now to FIG. 16, a support hoop including a radiopaque featureis disclosed. Support hoop 320, illustratively shown in the deployedstate, comprises articulation region 321, curved regions 322, attachmentpoint 323, and wound radiopaque wire 324. In the preferred embodiment,wire 324 is platinum and is either round or a strip approximately 0.001″in diameter. Wire 324 is wrapped around hoop 320 all along itscircumference.

One method of making a vascular device radiopaque is to electroplateplatinum or gold onto the device. However, electroplating can be complexand expensive, and may cause manufacturing difficulties. Because thehoop must change shape during deployment and retrieval, increasedthickness or flaking of plated gold are undesirable characteristics andmay promote failure of the support hoop. By wrapping wire 324, hoop 320maintains its strength and flexibility. Radiopaque wire 324 may be usedin conjunction with any of the vascular devices discussed herein.Radiopaque wire 324 may further be used with a wide variety of othervascular filter devices, as are known in the art.

Referring now to FIGS. 17A-17C, another alternative embodiment of thevascular device of the present invention is described. As illustrated inFIG. 17A, vascular device 330 comprises guide wire 332 with distalregion 333, wishbone sup port hoop 335, and blood permeable sac 336.Wishbone hoop 335 comprises spines 337 and 338 separated by a gap thatserves as articulation region 339. Articulation region 339 is shown ingreater detail in FIG. 17B, which corresponds to the area circled inFIG. 17A taken along section line B-B. Blood permeable sac 336 iswrapped around and attached to itself all along its perimeter, creatinghem bond 340 and lumen 341. Sac 336 includes pores 347. Lumen 341 isconfigured to receive spines 337 and 338 and bridge the gap betweenthem. FIG. 17C is a sectional view taken along line C-C of FIG. 17A,showing hem bond 340 and lumen 341 with spine 338 passing there through.

Referring again to FIG. 17A, wishbone support hoop 335 is attached tosheath 343 at attachment point 344. Sheath 343 is similar to sheath 302of the embodiment of FIG. 14, and preferably comprises a flexible,0.001″ thick tube made of a biocompatible material, such as polyamide orpolytetraethylene. Distal end 333 of guide wire 332 passes through thelumen of sheath 343. Sheath 343 may rotate with respect to guide wire332 but is translationally restrained by stops 345 and 346, for example,solder beads. Sheath 343 mitigates rotational problems by onlytransmitting translational motion of guide wire 332 to wishbone hoop335. Twisting moments applied to wire 332 do not affect the performanceof vascular device 330.

The wishbone design of support hoop 335 advantageously enables a widervariety of materials to be used to fabricate the support hoop.Articulation region 339 allows vascular device 330 to deploy andcontract in a manner similar to that described above for alternativeembodiments. Deployment and refraction of wishbone hoop 335 inducesminimal deformation of spines 337 and 338, thereby permitting use ofmaterials such as spring steel. As will of course be apparent, thesupport hoop of the embodiment of FIGS. 17A-17C may advantageously beincorporated in any of the foregoing embodiments.

Referring now to FIGS. 18A and 18B, an integrated vascular devicesuitable for thrombectomy is described. The integrated device comprisesa thrombectomy element and a vascular filter. In a preferred embodiment,the thrombectomy element is similar in construction to vascular filter20 described above and is connected to the guide wire proximal of thevascular filter. Alternatively, the thrombectomy element may be disposedon a separate catheter. The thrombectomy element may be retractedindependently of the vascular filter.

In FIG. 18, integrated vascular device 350 comprises guide wire 351,thrombectomy element 352 including support hoop 353 and blood permeablesac 354, and vascular filter element 355 including support hoop 356 andblood permeable sac 357. Filter hoop 356 is attached to guide wire 351while thrombectomy hoop 353 is attached to ring 358. Ring 358 isattached to pull wire 359 and has a bore through which guide wire 351passes. Ring 358 therefore acts as a linear bearing and allowsthrombectomy hoop 353 to be moved by pull wire 359 independently ofguide wire 351. Alternatively, thrombectomy element 352 may omit sac 354and simply comprise a wire hoop; in this case severed thrombus iscaptured by vascular filter 355.

In FIG. 18A, support hoops 353 and 356 and blood permeable sacs 354 and356 are contracted to a delivery state within lumen 360 of deliverysheath 361. Delivery sheath 361 includes nose cone 362 affixed to distalregion 363 of guide wire 351. In FIG. 18B, integrated vascular device350 is shown deployed in a vessel. As illustrated in FIG. 18B, vascularfilter 355 expands to engage the perimeter of the vessel and preventthrombus from bypassing the blood permeable sac, while thrombectomyelement 352 engages the vessel wall proximal of vascular filter 355. Asdescribed hereinbelow, proximal movement of thrombectomy device 352scrapes thrombus from the wall of the vessel when pull wire 359 pullsring 358 and support hoop 353 proximally.

Referring now to FIGS. 19A-19E, an illustrative method of using theintegrated vascular device of the present invention for thrombectomy isdescribed. In FIG. 19A, guide wire 351 is manipulated into positionproximal to thrombus T within vessel V using well-known percutaneoustechniques. Vascular device 350 of FIGS. 18A and 18B is disposed in itscontracted delivery state within the distal end of delivery sheath 361and the delivery sheath is advanced through the vessel using distal end363 of guide wire 351. The sides of support hoops 353 and 356 are foldedtogether and become elongated when drawn within delivery sheath 361, asdescribed with respect to vascular device 20 of FIGS. 2-4.

With respect to FIG. 19B, once delivery sheath 361 is disposed at thedesired location proximal to thrombus T within a patient's vessel V,such as a coronary artery or carotid artery, based on the position of,for example, radiopaque bands under a fluoroscope, integrated vasculardevice 350 is advanced through thrombus T. Distal end 363 of guide wire351 is advanced through the lesion, then nose cone 362 graduallyincreases the diameter of the void within thrombus T so that theremainder of delivery sheath 361 can be advanced far enough thatthrombectomy element 352 (still within delivery sheath 361) is locateddistal to thrombus T.

With integrated vascular device 350 in position, guide wire 351 is heldstationary while delivery sheath 361 is retracted proximally, as seen inFIG. 19C. Alternatively, delivery sheath 361 may be held stationarywhile guide wire 351 is advanced. In either case, when vascular device350 is no longer confined within delivery sheath 361, support hoops 353and 356 expand to seal against the walls of the vessel V and deployblood permeable sacs 354 and 357, respectively. Blood continues to flowthrough vessel V in direction A, impeded only by thrombus T.

In FIG. 19D, once vascular device 350 is deployed in vessel V, thrombusT is removed in the following manner. Vascular filter support hoop 353is rigidly attached to guide wire 351, while thrombectomy support hoop353 is attached to pull wire 359 via ring 358. Thrombectomy element 352then is refracted proximally to scrape along the wall of the vessel V bymotion at the proximal end of pull wire 359. Thrombus T, locatedproximal to thrombectomy element 352, is excised so that it is capturedin blood permeable sac 354 during the retraction.

With respect to FIG. 19E, once thrombus T has been captured within sac354, pull wire 359 is pulled proximally to cause the sides ofthrombectomy support hoop 353 to collapse together to close the mouth ofsac 354 (see FIG. 3). Additional proximal retraction of pull wire 359causes support hoop 353 and sac 354 to enter within lumen 360 ofdelivery sheath 361, restoring normal blood flow to vessel V. Meanwhile,vascular filter 355 is in a position distal to thrombectomy element 352to trap emboli E, i.e., pieces of plaque dislodged from either thrombusT or the walls of vessel V by thrombectomy element 352. Once any emboliE have been collected, filter hoop 356 and sac 357 are retracted intodelivery sheath 361 by motion at the proximal end of guide wire 351, ina manner similar to the retraction of hoop 353 and sac 354. Once guidewire 351 has been fully retracted, and nose cone 362 at the distal end363 of guide wire 351 is again in contact with delivery sheath 361, thedelivery sheath is withdrawn with integrated vascular device 350, thetrapped thrombus T, and any trapped emboli E.

As with previous embodiments, the compliant design of integratedvascular device 350 permits the device to be contracted to its deliverystate within the guide wire lumen of conventional previously knowninterventional devices, thereby reducing time, effort, and trauma. Thevascular device may be readily closed and retrieved upon completion ofthe interventional procedure.

Referring now to FIGS. 20A and 20B, an alternative embodiment of theintegrated vascular device is described. Integrated vascular device 370comprises guide wire 371, thrombectomy element 372, and vascular filter373 having support hoop 374 and blood permeable sac 375. Filter hoop 374is attached to guide wire 371, while thrombectomy element 372 isdisposed to slide along guide wire 371. Alternatively, thrombectomyelement 372 may be disposed on a separate catheter element that extendseither through lumen 377 of delivery sheath 378 or is separatelydisposed proximal to vascular filter 373. FIG. 20A shows thrombectomyelement 372 and vascular filter 373 contracted in a delivery statewithin lumen 377 of delivery sheath 378. Delivery sheath 378 includesnose cone 379 affixed to distal region 380 of guide wire 371. In FIG.20B, integrated vascular device 370 is shown in the deployed state.

Thrombectomy element 372 may comprise any of a family of knownthrombectomy, atherectomy, or, alternatively, drug delivery devicessuitable for use in conjunction with vascular filter 373. Thrombectomyelement 372 may, for example, comprise any of: a rotary ablation device,such as described in U.S. Pat. No. 4,867,156 to Stack et al., U.S. Pat.No. 4,990,134 to Auth, and U.S. Pat. No. 5,314,407 to Auth et al.; anatherectomy technology, such as described in U.S. Pat. No. 5,181,920 toMueller et al., and U.S. Pat. No. 5,074,841 to Ademovic et al.; or aballoon embolectomy technology, such as described in U.S. Pat. No.3,923,065 to Nozick et al., U.S. Pat. No. 5,769,871 to Mers Kelly etal., U.S. Pat. No. 5,192,290 to Hilal, U.S. Pat. No. 5,112,347 toTaheri, and U.S. Pat. No. 4,030,503 to Clark III. All of the foregoingpatents are incorporated herein by reference. Thrombectomy element 372may alternatively comprise a wire loop or ring, such as described forthe embodiment of FIGS. 18A and 18B, a laser ablation device, a chemicalflushing system, etc.

Referring now to FIGS. 21A and 21B, a delivery system configured for usewith embodiments of the present invention is described. The deliverysystem facilitates deployment and retrieval of the embodiments byintegrating the functions of a torquer, a Touhy Borst adapter, and apusher into a single device. In FIG. 21, the delivery system isillustratively used in conjunction with vascular device 20 of FIGS. 2-5.In FIG. 21A, vascular device 20 is in the retracted deliveryconfiguration, while in FIG. 21B vascular device 20 is in the expandeddeployed configuration. Delivery system 450 comprises proximal screw cap452, collet 456, handle 460, rod 464, central screw cap 468, lumenflushing section 472, distal hub 479, and nose piece 486.

Proximal screw cap 452 includes bore 453 with female screw thread 454and guide wire lumen 455. Bore 453 extends proximally from the distalface of cap 452. Guide wire lumen 455 extends from the proximal end ofbore 453 to the proximal end of cap 452.

Handle 460 comprises proximal male screw thread 461 configured to engagefemale screw thread 454 of cap 452, and lumen 462 configured to receivecollet 456 in its proximal end and rod 464 in its distal end. Lumen 462has a reduced diameter at the distal end of handle 460 that captures astep on the proximal end of rod 464. Thus, while collet 456 is removablereceived within lumen 462, rod 464 may translate and rotate within, butmay not be removed from, lumen 462. Guide wire 422 freely passes throughcollet 456 when screw cap 452 is not securely fastened to handle 460.When cap 452 is securely fastened to handle 460, it causes collet 456 toelastically deform, decreasing the diameter of the lumen extendingthrough the collet, and frictionally locking guide wire 422 into rigidattachment with collet 456. Guide wire 422 is thereby rigidly connectedto handle 460.

Rod 464 further comprises guide wire lumen 465 extending therethrough.Rod 464 has its distal end rigidly and permanently affixed to centralscrew cap 468. Cap 468 comprises female screw thread 469 and lumen 470.Lumen 470 includes a proximal reduced-diameter step that captures rod464 within the proximal end of cap 468, and a distal portion thatreceives lumen flushing or fluid port section 472.

Section 472 comprises male screw thread 473, side port 474, bore 475,guide wire lumen 476, and fluid lumen 477. Male screw thread 473 isconfigured to engage female thread 469 of cap 468. Section 472 includesa flange disposed just distal of thread 473 that is captured withinlumen 470 of cap 468. Thus, cap 468 may be tightened onto and loosenedfrom, but not removed from, section 472.

Rod 464 is received within bore 475 of section 472. Guide wire 22 passesbetween bore 475 and fluid lumen 477 within guide wire lumen 476. Fluidlumen 477 connects side port 474 to the guide wire lumen of deliverysheath 40. O-rings 478 provide a fluid seal at the distal end of lumen477.

Distal hub 479 connects section 472 to nose piece 486. Hub 479 comprisesbore 483, female screw thread 484, and annulus 485 containing taperedprojection 481. Bore 483 includes flange 482 that rotatably receivessection 472 in its proximal end. Nose piece 486 comprises male screwthread 487, tapered bore 488, and delivery sheath lumen 489. Male screwthread 487 is configured to engage female thread 484 in annulus 485 ofhub 479. Tapered bore 488 allows tapered projection 481 of hub 479 toextend within nose piece 486 and permit delivery sheath 40 from deliverysheath lumen 489 to extend therethrough. O-rings 478 are disposedbetween the hub 479 and nose piece 486 and between hub 479 and section472.

Delivery system 450 advantageously may be implemented in a variety ofways. For example, the delivery system may be offered with a deliverycatheter or sheath pre-attached. In this embodiment, proximal screw cap452 is loosened, and the proximal end of guide wire 22 may be passedthrough the delivery catheter or sheath, and delivery system 450, untilvascular device 20 is in its retracted state within the deliverycatheter or sheath. Insertion of the vascular device into the patientmay then proceed. Alternatively, delivery system 450 may be commerciallysupplied in the configuration shown in FIG. 5A, i.e., pre-loaded with adelivery catheter or sheath, such as sheath 40, already attached and avascular device, such as vascular device 20, retracted therein. Asanother alternative, delivery system 450 may be offered without either adelivery sheath or vascular device attached, or the delivery catheter orsheath may be an interventional instrument, such as an angioplasty,atherectomy, or stent delivery catheter.

Referring again to FIGS. 5A-5D in conjunction with FIGS. 21A and 21B, amethod of using the delivery system of the present invention inconjunction with a vascular filter is described. With vascular device 20contracted within distal end 42 of delivery sheath 40 (FIGS. 5A and21A), delivery sheath 40 is attached to delivery system 450 by looseningproximal screw cap 452 and extending the proximal end of guide wire 22through delivery system 450, with handle 460 in its proximal-mostposition (FIG. 21A). Screw cap 452 is then tightened to cause collet 456to engage guide wire 22 to handle 460.

Delivery sheath 40 then is advanced through a patient's vasculatureusing well-known percutaneous techniques using distal end 23 of guidewire 22. If a vessel bifurcation is to be crossed during advancement,handle 460 may be rotated to divert the distal end of sheath 40 into thedesired branch of the bifurcation. The rotational moment or torqueapplied to handle 460 is transmitted to guide wire 22 (when screw cap452 is tightened), which causes distal end 23 to rotate and facilitatespositioning of vascular device 20 in the proper side of the bifurcation.As shown in FIG. 5A, advancement continues until delivery sheath 40 isdisposed at a desired location within a patient's vessel V, such as acoronary or carotid artery, as determined, for example, by the positionof radiopaque band 43 under a fluoroscope.

With the vascular device in position, handle 460, and thus guide wire22, is held stationary while section 472 and attached delivery sheath 40are retracted proximally. Alternatively, handle 460 may be advancedwhile section 472 and sheath 40 are held stationary. In either case,when vascular device 20 is no longer confined within delivery sheath 40,support hoop 24 expands to seal against the walls of the vessel V, asdepicted in FIGS. 5B and 21B. Blood continues to flow unimpeded throughvessel V in direction A.

Depending on the medical procedure prescribed in conjunction with theuse of vascular device 20, delivery sheath 40 may retrieve vasculardevice 20 at the conclusion of the procedure, or sheath 40 may bedetached from delivery system 450 and removed from the patient. Ifsheath 40 is detached, guide wire 22 may be removed from delivery system450 so that other interventional instruments, such as angioplastycatheters, atherectomy devices, or stent delivery systems may beadvanced along guide wire 22 to position such devices at treatment zoneslocated proximally of vascular device 20. Guide wire 22 and theinterventional catheter then may be passed through and fastened todelivery system 450. For example, as shown in FIG. 5C, angioplastyballoon catheter 44 may be advanced along guide wire 22 to a positionproximal of vascular device 20 so that device 20 may trap emboli E,i.e., pieces of plaque dislodged from the walls of vessel V by balloon46.

Upon completion of the angioplasty procedure using angioplasty ballooncatheter 44, handle 460 with attached guide wire 22 is pulled proximallyto cause the sides of support hoop 24 to collapse together to close themouth of sac 28 (FIG. 3). Additional proximal retraction of guide wire22 causes support hoop 24 and sac 28 to enter at least partially withinthe guide wire lumen of angioplasty catheter 44. As depicted in FIG. 4D,only a portion of support hoop 24, near articulation region 26, and adistal portion of sac 28 extend out of the guide wire lumen ofangioplasty catheter 44. Angioplasty catheter 44 then is withdrawn withvascular device 20 and any trapped emboli E.

It also may be beneficial during a medical procedure to introduce orwithdraw fluids from the operative site. For example, it may bebeneficial to deliver medicaments, or draw suction to remove blood. Thedelivery sheath lumen also may require flushing with saline to preventclotting within the lumen. These and other procedures are made possibleby side port 474 of section 472, which, as described hereinabove, is influid communication with the lumen of delivery sheath 40.

In addition to applications with vascular filters, delivery system 450may be used as part of the thrombectomy/embolectomy procedure describedherein above, as well as in a variety of other procedures.

Embodiments of the present invention may optionally be used inconjunction with a specially configured retrieval sheath. Applicant hasdetermined that bunching of sac 28 in FIG. 5D may occur duringretraction into catheter 44, resulting in a retrieval profile that maybe difficult to navigate through a patient's vasculature. However,additional proximal retraction of guide wire 22 in an attempt todecrease the profile of sac 28 may generate stress loads sufficient totear sac 28 and release captured emboli.

With reference to FIGS. 22A-22E, a specially configured retrieval sheathand methods of use with the vascular device of the present invention aredescribed. As with FIG. 5, sizes have been exaggerated to illustratestructure. In FIG. 22A, guide wire 556 is positioned within vessel Vusing well-known percutaneous techniques. Vascular device 550 isdisposed in its contracted delivery state within distal end 554 ofdelivery sheath 552. Retrieval sheath 560 and guide catheter 562 areadvanced over delivery sheath 552 to a position located just proximal ofdistal end 554.

Retrieval sheath 560 includes collapsible flared end region 564, whichis shown in a contracted delivery state within catheter 562 in FIG. 22A.Flared end region 564 has a deployed state, wherein the wall flaresoutward to form a frustrum of a cone, and a contracted state, whereinthe wall is substantially cylindrical. Flared end region 564 preferablyincludes radiopaque band 566.

With respect to FIG. 22B, once delivery sheath 552 is disposed at adesired location within a patient's vessel V, guide wire 556 is heldstationary while delivery sheath 552 is retracted proximally.Alternatively, delivery sheath 552 may be held stationary while guidewire 556 is advanced. In either case, when vascular device 550 is nolonger confined within delivery sheath 552, support hoop 568 andattached blood permeable sac 570, expands to seal against the walls ofthe vessel V. Sac 570 further comprises radiopaque band 572. When in thedeployed state, the curved regions of support hoop orient itsarticulation region concentrically against the inside wall of thevessel. Blood continues to flow unimpeded through vessel V in directionA.

With vascular device 550 deployed, an interventional procedure isperformed proximal of the device. For example, guide catheter 562 may bean angioplasty balloon catheter similar to catheter 44 of FIGS. 5C and5D. The interventional procedure generates emboli E proximal of device550, which travel downstream and are captured in sac 570.

With respect to FIG. 22C, upon completion of the interventionalprocedure, guide wire 556 is pulled proximally to cause the sides ofsupport hoop 568 to collapse together to close the mouth of sac 570 (seeFIG. 3). Additional proximal retraction of guide wire 556 causes supporthoop 568 and sac 570 to partially enter within distal end 554 ofdelivery sheath 552. If bunching of the sac is anticipated or suspected,flared sheath 560 may be advanced distally to expand end region 564,which comprises a suitable elastomeric material, such as latex, rubber,or a synthetic variant thereof.

As depicted in FIG. 22D, delivery sheath 552 is retracted proximallywhile retrieval sheath 560 is held stationary, until radiopaque bands572 and 566 are concentrically aligned, as determined, for example, witha fluoroscope. Then, as illustrated in FIG. 22E, sheaths 552 and 560 aresimultaneously withdrawn proximally while guide catheter 562 is heldstationary. This motion causes flared end region 564 to collapse sac 570to its contracted state. In so doing, flared end region 564 applies adistributed load over the surface of sac 570, thereby decreasing theretrieval profile of sac 570 with reduced risk of rupture of sac 570.

Vascular device 550 also may be used in performingthrombectomy/embolectomy. In this case, vascular device 550 is advancedin its retracted state within delivery sheath 552 to a location distalof a lesion. Delivery sheath 552 is withdrawn proximally, and vasculardevice 550 is deployed. With support hoop 568 in contact with the vesselwall, vascular device 550 may be retracted proximally to scrape alongthe wall of the vessel and excise thrombus so that it is captured in sac570. Delivery sheath 552, as well as flared sheath 560 and guidecatheter 562, then may be reinserted into the vessel along guide wire556, and vascular device 550 may be refracted and removed from thevessel in the manner described hereinabove.

With reference to FIGS. 23A and 23B, an alternative embodiment of thespecially configured retrieval sheath, and methods of use with thevascular device of the present invention, are described. Again, sizeshave been exaggerated to illustrate structure. In FIG. 23A, guide wire582 has been positioned within vessel V using well-known percutaneoustechniques. Vascular device 580 has been expanded to its deployed stateafter delivery within delivery sheath 584, in the manner discussedhereinabove. Support hoop 586 seals against the walls of vessel V, andblood permeable sac 588 is positioned to capture emboli E generated by,for example, an upstream interventional procedure. Blood continues toflow unimpeded through vessel V in direction A.

Delivery sheath 584 further comprises atraumatic expander 590 disposedon a distal end. Retrieval sheath 592 is advanced over delivery sheath584 to a position located just proximal of expander 590. Retrievalsheath 592 includes expandable end region 594, which is shown in acontracted delivery state in FIG. 23A. Expandable end region 594 has adeployed state, wherein the wall flares outward to form a frustrum of acone, and a contracted state, wherein the wall is substantiallycylindrical. Expander 590 has a larger maximum diameter than end region594. Expandable end region 594 preferably includes radiopaque band 596,while expander 590 preferably includes radiopaque band 598 so that theirpositions relative to one another may be accurately determined.

With respect to FIG. 23B, upon completion of the interventionalprocedure, guide wire 582 is pulled proximally to cause the sides ofsupport hoop 586 to collapse together to close the mouth of sac 588 (seeFIG. 3). Additional proximal retraction of guide wire 582 causes supporthoop 586 and sac 588 to partially enter within the distal end ofdelivery sheath 584.

If bunching of the sac is anticipated or suspected, delivery sheath 584may be retracted proximally while retrieval sheath 592 is heldstationery to expand end region 594 of retrieval sheath 592 withexpander 590. Delivery sheath 584 is retracted a sufficient distance toprotect sac 588 and its embolic contents within end region 594. Thedistance may be determined by means of radiopaque bands 596 and 598. Endregion 594 comprises a suitable elastomeric material, such as latex,rubber or a synthetic variant thereof.

The profile of end region 594 in the expanded state allows forretraction of retrieval sheath 592, as well as delivery sheath 584 andvascular device 580 disposed therein, in a manner that mitigatesdangerous interaction with the vascular wall. It also allows vasculardevice 580 to be retrieved in a partially collapsed state that reducesthe risk of sac 588 tearing. As with vascular device 550, vasculardevice 580 may be used in performing thrombectomy/embolectomy.

The support hoops depicted herein illustratively are shown as oval orheart-shaped in the deployed state, where the shape is exaggerated forthe sake of clarity. In preferred embodiments, the support hoops aresubstantially round when deployed, to ensure contact around thecircumference of the support hoop and provide a positive seal againstthe arterial wall.

Although preferred illustrative embodiments of the present invention aredescribed above, it will be evident to one skilled in the art thatvarious changes and modifications may be made without departing from theinvention. It is intended in the appended claims to cover all suchchanges and modifications that fall within the true spirit and scope ofthe invention.

What is claimed is:
 1. An embolic protection filtering device,comprising: an elongate shaft having a proximal region and a distalregion; a filter affixed to the shaft adjacent the distal region; a noseassembly having a proximal end and a distal end, the nose assemblyaffixed to the shaft adjacent to and distal of the filter; and adelivery sheath slidably disposed over the elongate shaft, the deliverysheath having a first outer diameter along a majority of its length,wherein the nose assembly has a diameter at its proximal endsubstantially equal to the first outer diameter of the delivery sheath.